What Is The Purpose Of Pile Driving?
Pile driving may not be feasible if there is a hospital or school close to the proposed site. In such situations, jacking of piles can be used to avoid noise. If the proposed building has a basement, underpinning of nearby buildings may be necessary (Figure ). Figure
Pile driving is a critical part of the construction process. Vertical columns made of various materials (wood, concrete, steel, or a combination) are driven into un-excavated soil. The piles are a type of deep foundation used to hold up large structures – often bridges. In this we discuss pile driving basics, the common problems.
Pile driver – Wikipedia
Pile driving synonyms, Pile driving pronunciation, Pile driving translation, English dictionary definition of Pile driving. n. A machine that drives a pile by raising a weight between and dropping it on the head of the pile.
Please wait while your request is being verified…
A mechanically sound drawing of a pile driver appeared as early as in Francesco di Giorgio Martini ‘s treatise Trattato di Architectura. However, there is evidence that a comparable device was used in the construction of Crannogs at Oakbank and Loch Tay in Scotland as early as years ago.
Modern piledriving equipment variously uses hydraulics, steam, diesel, or electric power to raise the weight and guide the pile. Diesel hammer[ edit ] A modern diesel pile hammer is a large two-stroke diesel engine. The weight is the piston , and the apparatus which connects to the top of the pile is the cylinder. Piledriving is started by raising the weight; usually a cable from the crane holding the pile driver — This draws air into the cylinder. Diesel fuel is injected into the cylinder.
The weight is dropped, using a quick-release. The mixture ignites, transferring the energy of the falling weight to the pile head, and driving the weight up. The rising weight draws in fresh air, and the cycle continues until the fuel is depleted or is halted by the crew.
As the piston falls, it activates the fuel pump, which discharges a metered amount of fuel into the ball pan of the impact block. The falling piston blocks the exhaust ports, and compression of fuel trapped in the cylinder begins. The compressed air exerts a pre-load force to hold the impact block firmly against the drive cap and pile. At the bottom of the compression stroke, the piston strikes the impact block, atomizing the fuel and starting the pile on its downward movement.
In the instant after the piston strikes, the atomized fuel ignites, and the resulting explosion exerts a greater force on the already moving pile, driving it further into the ground. The reaction of the explosion rebounding from the resistance of the pile drives the piston upward. As the piston rises, the exhaust ports open, releasing the exhaust gases to the atmosphere. After the piston stops its upward movement, it again falls by gravity to start another cycle.
Vertical travel lead systems[ edit ] Berminghammer vertical travel leads in use Military building moblie unit on " Army " exhibition Vertical travel leads come in two main forms: spud and box lead types. Hydraulic hammer[ edit ] A hydraulic hammer is a modern type of piling hammer used instead of diesel and air hammers for driving steel pipe, precast concrete , and timber piles.
In many cases the dominant noise is caused by the impact of the hammer on the pile, or the impacts between components of the hammer, so that the resulting noise level can be similar to diesel hammers. This system is preferred where vibration is a concern.
There are press attachments that can adapt to conventional pile driving rigs to press 2 pairs of sheet piles simultaneously. Other types of press equipment sit atop existing sheet piles and grip previously driven piles. Such equipment and methods are specified in portions of the internal drainage system in the New Orleans area after Hurricane Katrina , as well as projects where noise, vibration and access are a concern.
Vibratory hammers can drive or extract a pile. Extraction is commonly used to recover steel I-beams used in temporary foundation shoring. Hydraulic fluid is supplied to the driver by a diesel engine-powered pump mounted in a trailer or van, and connected to the driver head via hoses. When the pile driver is connected to a dragline excavator , it is powered by the excavator’s diesel engine.
Vibratory pile drivers are often chosen to mitigate noise, as when the construction is near residences or office buildings, or when there is insufficient vertical clearance to permit use of a conventional pile hammer for example when retrofitting additional piles to a bridge column or abutment footing. Hammers are available with several different vibration rates, ranging from vibrations per minute to VPM.
The vibration rate chosen is influenced by soil conditions and other factors, such as power requirements and equipment cost. Such rigs are similar in function to oil drilling rigs, and can be equipped with a short screw for dry soil , rotary bucket for wet soil or core drill for rock , along with other options. Expressways, bridges, industrial and civil buildings, diaphragm walls, water conservancy projects, slope protection, and seismic retrofitting are all projects which may require piling rigs.
Environmental effects[ edit ] The underwater sound pressure caused by pile-driving may be deleterious to nearby fish. Mitigation methods include bubble curtains , balloons, internal combustion water hammers.